Sheave



(No Model.)

P. B. TORRBY.

SHEAVB.

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m Mm@ UNITED STATES PATENT OFFICE.

.FRANCIS B. TORREY, OF BATH, MAINE.

S H EAV E SPECIFICATION forming part of Letters Patent No. 499,611, dated J une 13, 1893.

Application filed June 1'7, 1892. Serial No. 437,050. (No model.)

To all whom it may concern:

Be it known that I, FRANCIS B. TORREY, a citizen of the United States of America, residing at Bath, in the county of Sagadahoc and State of Maine, have invented certainl new and useful Improvements in Sheaves, of which the following is a specification.

In the manufacture of sheaves, particularly of sheaves designed to be used in pulley blocks of ships and for like purposes, it is desirable to reduce as much as possible, the weight of the sheave, to increase its durability, and to provide anti-friction devices to facilitate free running, without frictional heat. At the same time the ordinary requirement of economy in the manufacture must be heeded. In the invention hereinafter described I have made improvements with the view of meeting all the requirements above referred to.

My saidimprovements relate to the method of making such sheaves, and to the form or structure.

The form and mode of manufacture are illustrated in the accompanying drawings, in which- Figure lrepresents a side elevation of my improved sheave. Fig. 2 shows a central cross section of the same. Fig. 3-V is a perspective view of the parts of the frame which holds the anti-friction rollers. Fig. 4:- shows in cross section, the parts of the frame when put together, and Fig. 5- shows a portion of the sheave in central cross-section and illustrates the mode of casting the rim upon the wooden center of the wheel. Fig. 6 is a view of the chill used in casting the rim of the sheave. p

For the purpose of makinga sheave of light weight, the ordinary kinds of Wood have qualities adapted to meet the requirements of the ease. But ordinary woods of light weight, do not possess the necessary strength in hardness upon the bearing faces, and it `is necessary to reinforce them on the rim and at the center. For reinforcement of the rim various constructions have heretofore been devised. In a patent heretofore granted to myself, by the United States Patent Office, and numbered 221,879, of November, 1879, I have shown a rim of metal fusible at low temperature, cast upon the wooden center of a sheave. In the invention herein-described I have provided a cast rim of metal ordinarily used for strength and wear and better adapted for the rims of sheaves than the soft metallic composition, fusible at loW temperature. The difliculty heretofore experienced in attempting to cast arim of ordinarily used metals such as iron and brass upon a wooden sheave, arises from. the fact that the heat of such metals in a state of fusion, is so great that it destroys the wood. This I have overcome as hereinafter explained.

In the drawings A, represents the center of a sheave madev of wood, wood pulp, or any such fibrous material which may be used as a substitute for wood. Preferably (if of wood) it is made with the grain parallel with the axis and is treated with hot oil or parafine, or a mixture of both, to shrink it, expel the moisture, and fill the pores. In order to reduce the amount of metal in the rim and to form said rim with thickness of metal approximately uniform and thereby reduce the amount of heating eect at casting, I groove the rim of the Wooden center, on substantially the same curve of cross section, as that of theperipheryof the metal rim when completed. To give space for the side lianges 2, 2, of the rim B, I rabbet the edges of the center, on the outside. When the center has thus been properly shaped, it being of` a combustible nature, I cover it with a coating of some fire proof or non-conducting material, such as a mixture containing asbestus or plumbago, or asbestus and plumbago combined. This covering I prefer to extend over the sides of the wooden center as far as the metal Iianges of the bushing. This, it will be understood, covers also the grooved periphery and tends to resist the action of the heat of the molten metal, when that is east upon the center. I uponthis spin or otherwise form a covering of sheet metal, or equivalent material upon the grooved periphery. Such a covering is shown'at C. I prefer to use for this purpose thin steel, cut of proper Width and length, so that it may cover the groove from edge to edge, and that its ends may meet, when it is rolled or pressed upon the groove. This band or covering, if of steel or equivalent metal, serves the purpose also, of strengthening the sheave, in addition to the effect of resisting the heat of the fused ICO paint, or covering above described since the greater part of the fused metal bears thereon.

This heat is resisted by the reinforcing bandV and by the paint, and the wood is thus protected.

In the process of casting the rim, there are.

special points to be regarded.

As herein before explained, the groove in the wood conforms to the shape of the finished groove of the sheave. This prevents the introduction of the sheave into the mold, since the projecting edges of the rim would come into contact with the mold. To remedy this I use a divided ring D, the outside periphery. of which is plain, and the inner periphery; curved and in contour corresponding to the This ring forms` in fact, a part of the mold, and gives shape to In practice I make this ring of cast iron, and derive therefromA The edges of the ringj are united by dowels 3, 3. In the mold the; face of the cavity against which the periphery of the ringbears,is made cylindrical and plain, and the parts are so proportioned that thel ring lits snugly therein, and an annular space f is formed about the center, and between it The ring is separated and? placed about the center, Within its groove,

groove to be found thereon.

the periphery of the rim.

the effect of a chill.

and the ring.

and the dowels entered: then the center and ring together are placed in the mold, and the wooden part properly centered. Afterward: the metal is poured in to form the rim. The

That part of my invention which related to` the antifriction bearings of the sheave con.

sists in a special construction of the bushing,

and in the special construction of the frame|` which supports the anti-friction rollers.

I prefer to form one half of the barrel of the bushing in each, it being in the form of cylindrical iianges e, f. These rise from the in ner edges of the face flanges g, which eXtend inwardly, or what is for the same effect, thef bore of the barrel parts is tapering slightly, from theinner ends outwardly. One part has an outer rabbet 4 and the other an inner rab bet 5, fitted so that the ends unite, as seenf in Fig. 2. The bushing is made of cast iron,

this being for economy, but the inner faces of the barrel parts, are provided with brass These are cast into or upon I They an outer flange 7 which retains the anti-friction rollers.v The interior of each part is also slightly tapering outwardly from the center. Ordinarily the bearing surfaces are made smooth from the casting by boring out, but this removes the surface of the metal which is the best part. To remedy this I place within the faced, barrel part, a roller adapted to roll down the brass, and give it a smoothing and increased hardness at the same time that it is properly shaped, by turning the roller in the bushing. This improves the skin of the casting and gives it also the proper shape. The two parts being completed, the frame holding the anti-friction rollers in place in one part, and entered on one side and the other part is placed in the other, the fianges fitting in rabbets in the center, while the rabbeted ends of the barrel parts unite and hold the rollers therein. The flanges are held by bolts passing through the wood.

The frame which holds the rollers serves simply to hold them in place and sustain no material strain. For cheapness and convenience of construction, I cast the two sides m, and n, separately, out of brass or similar material. Heretofore these frames have been made up of separate parts or cast entire; either way having its special disadvantages. As shown the two parts of my frame are duplicates. Each ring l0, has spurs 11, on which the rollers are centered. As heretofore made these have been cast cylindrical and required fitting. I have formed them conical as shown and made the holes in the ends of the rollers also conical, so that as they come from the molds the spurs fit the holes and center the rollers, without any machine work. I also cast the bars 12, integral with the ring at one end only. The other ends are cast tapering, as shown. To receive these tapered ends I punch or drill holes in each opposite ring, inclined, as shown, so that the tapering ends of the ba-r are forced in, when the parts are pressed together, and thus clinched. Each part is cast with three bars, the holes alternating regularly, and when they are put together the parts are at l equal distances and have the spurs between The bushing is made in two parts E,.and F.

each adjacent pair of bars.

I claiml. A sheave composed of a center of fibrous material, having a grooved periphery and a cast metal grooved rim, conforming to the said grooved periphery and provided with in'- terposed heat resisting covering placed within the said grooved periphery, substantially as described.

2. A sheave composed of a center of fibrous material, having a grooved periphery and a cast metal grooved rim conforming to said grooved periphery, and provided with a projecting interposed band between said rim and the said periphery, substantially as described. 3. A sheave composed of a center of fibrous material having a grooved periphery and a IOO IIC

grooved periphery, and provided with an inner covering of heat resisting paint, and an outer covering of metal between the cast rim and the center, substantially as described.

4. A sheave consisting of a wood center having a grooved periphery, with its grain in lines parallel with the axis of said center, in combination with a metal band covering the grooved periphery and a cast metal grooved rim upon said band, substantially as described.

5. A sheave consisting of a iibrous center and an outer metal rim combined with a cast iron divided bushing, having a brass lining, substantially as described.

G. In combination, with a sheave having bushing, a frame for holding the anti-friction rollers, said frame being cast in duplicate FRANCIS B. TORREY.

Witnesses:

HENRY E. COOPER, WALTER P. KEENE. 

